Form not submitting Feedback http error 500

Hi,

Form submissions are not working. Errors listed below:

POST http://dev.careshop.starfi.sh/wp-json/contact-form-7/v1/contact-forms/412/feedback 500 (Internal Server Error)

{“code”:”rest_no_route”,”message”:”No route was found matching the URL and request method”,”data”:{“status”:404}}

I already tried different solutions but nothing works.
1. fixed .htaccess
2. Deactivate Multilingual plugins and theme

The page I need help with: [log in to see the link]